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@ 2022-11-21 11:54 Pingfan Liu
  2022-11-21 11:57 ` // a kdump hang caused by PPC pci patch series Pingfan Liu
  0 siblings, 1 reply; 6+ messages in thread
From: Pingfan Liu @ 2022-11-21 11:54 UTC (permalink / raw)
  To: linuxppc-dev; +Cc: Coiby Xu, Cédric Le Goater

[-- Attachment #1: Type: text/plain, Size: 1322 bytes --]

Hello Powerpc folks,

I encounter an kdump bug, which I bisect and pin commit 174db9e7f775
("powerpc/pseries/pci: Add support of MSI domains to PHB hotplug")

In that case, using Fedora 36 as host, the mentioned commit as the
guest kernel, and virto-block disk, the kdump kernel will hang:

[    0.000000] Kernel command line: elfcorehdr=0x22c00000
no_timer_check net.ifnames=0 console=tty0 console=hvc0,115200n8
irqpoll maxcpus=1 noirqdistrib reset_devices cgroup_disable=memory
     numa=off udev.children-max=2 ehea.use_mcs=0 panic=10
kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd
hugetlb_cma=0
    ...
    [    7.763260] virtio_blk virtio2: 32/0/0 default/read/poll queues
    [    7.771391] virtio_blk virtio2: [vda] 20971520 512-byte logical
blocks (10.7 GB/10.0 GiB)
    [   68.398234] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 is taking a long time
    [  188.398258] systemd-udevd[187]: virtio2: Worker [190]
processing SEQNUM=1193 killed

During my test, I found that in very rare cases, the kdump can success
(I guess it may be due to the cpu id).  And if using either maxcpus=2
or using scsi-disk, then kdump can also success.  And before the
mentioned commit, kdump can also success.

The attachment contains the xml to reproduce that bug.

Do you have any ideas?

Thanks

[-- Attachment #2: virtblk-hang.xml --]
[-- Type: text/xml, Size: 3275 bytes --]

<domain type="kvm">
  <name>rhel9</name>
  <uuid>6266c1c1-1e74-4046-b959-33d94877b387</uuid>
  <metadata>
    <libosinfo:libosinfo xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0">
      <libosinfo:os id="http://redhat.com/rhel/8-unknown"/>
    </libosinfo:libosinfo>
  </metadata>
  <memory unit="KiB">16777216</memory>
  <currentMemory unit="KiB">16777216</currentMemory>
  <vcpu placement="static">16</vcpu>
  <os>
    <type arch="ppc64le" machine="pseries-rhel8.6.0">hvm</type>
    <boot dev="hd"/>
  </os>
  <cpu mode="custom" match="exact" check="none">
    <model fallback="forbid">POWER9</model>
  </cpu>
  <clock offset="utc"/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>destroy</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type="file" device="disk">
      <driver name="qemu" type="qcow2"/>
      <source file="/var/lib/libvirt/images/rhel-guest-image-9.1-20220701.0.ppc64le.qcow2"/>
      <target dev="vda" bus="virtio"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x04" function="0x0"/>
    </disk>
    <controller type="usb" index="0" model="qemu-xhci" ports="15">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x02" function="0x0"/>
    </controller>
    <controller type="pci" index="0" model="pci-root">
      <model name="spapr-pci-host-bridge"/>
      <target index="0"/>
    </controller>
    <controller type="virtio-serial" index="0">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x03" function="0x0"/>
    </controller>
    <interface type="network">
	    <mac address="52:54:00:74:c9:50"/>
	    <source network="default"/>
	    <model type="virtio"/>
	    <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>
    </interface>
    <serial type="pty">
      <target type="spapr-vio-serial" port="0">
        <model name="spapr-vty"/>
      </target>
      <address type="spapr-vio" reg="0x30000000"/>
    </serial>
    <console type="pty">

      <target type="serial" port="0"/>
      <address type="spapr-vio" reg="0x30000000"/>
    </console>
    <channel type="unix">
      <target type="virtio" name="org.qemu.guest_agent.0"/>
      <address type="virtio-serial" controller="0" bus="0" port="1"/>
    </channel>
    <input type="tablet" bus="usb">
      <address type="usb" bus="0" port="1"/>
    </input>
    <input type="keyboard" bus="usb">
      <address type="usb" bus="0" port="2"/>
    </input>
    <tpm model="tpm-spapr">
      <backend type="emulator" version="2.0"/>
      <address type="spapr-vio" reg="0x00004000"/>
    </tpm>
    <graphics type="vnc" port="-1" autoport="yes">
      <listen type="address"/>
    </graphics>
    <audio id="1" type="none"/>
    <video>
      <model type="vga" vram="16384" heads="1" primary="yes"/>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x07" function="0x0"/>
    </video>
    <memballoon model="virtio">
      <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0"/>
    </memballoon>
    <rng model="virtio">
      <backend model="random">/dev/urandom</backend>
      <address type="pci" domain="0x0000" bus="0x00" slot="0x06" function="0x0"/>
    </rng>
    <panic model="pseries"/>
  </devices>
</domain>

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